Grinding machine



GRINDING MACHINE Original Filed June 10, 1951 12 Sheets-Sheet 1 V INVENTOR. C'LHRENCE c. STEVE/vs, BY

m HIS TTORNEK y 12, 3 c. c. STEVENS 2,040,449

' GRINDING MACHINE Original Filed June 10, 1931 12 Sheets-Sheet 2 FIG. 2

Q o no: a IGD .0 840 l D INVENTOR. CLHRENCE c. STEVE/V5, BY

y 6- c..c. STEVENS 2,040,449

GRINDING MACHINE Original Filed June 10, 1931 12 Sheets-$116M, 4

INVENTOR.

May 12, 1936. c. c. STEVENS GRINDING MACHINE l2 Sheets-Sheet 5 Original Filed June 10, 1931 FIG. lo'

v INVENTOR. CLHRENCE' c. $7El/EN5,

Hi5 fiTTORNE y 1936- v c. c. STEVENS 2,040,449

GRINDING MACHINE Original Filed June 10, 1931 12 Sheets-Sheet 7 7 INVENTOR. cmnzucs c. STEVENS,

HIS 0% May 12, 1936. CL STEVENS 2,040,449 GRINDING MACHINE Original Filed June 10, 1931 12 Sheets-Sheet 8 FIG. /5

x 472 /fi 49o 47a nz m O O f,"- 34a Mil, O

INVENTOR. CLHRENCE C. STEVE/V5,

His m'ronw May 12, 1936.

C. C. STEVENS GRINDING MACHINE Original Filed June 10, 1931 12 Sheets-Sheet 9 FIG. I?

INVENTOR.

CLHRENCE C. STEVENS,

H/Is nrromw:

May 12, 1936. Q Q STEVENS 2,040,449

' GRINDING MACHINE Original Fi led June 10. 1951 12 Sheets-Sheet 10 llvvsivroRi CLfiRE/VCE c 5 EMS,

His /7% May 12, 1936.

C.C.. STEVENS GRINDING MACHINE l2 Sheets-Sheet 11 Original Filed June 10, 1931 LIEL || Hill llll HHHH \HHHHHHHHI llll Vvir I II I NVEN TOR T T H a b H May 12, 1936.' ,c. c. STEVENS, 2 0,

' GRINDING MACHINE Original Filed June 10, 1951 12 Sheets-Sheet 12 v FIG. 52

45 Fig. 12 is a section on line Patented May 12 1936 UNITED STATES 2,040,449 GRINDING MACHINE- Clarence 0. Stevens, Forestville, Conm, assignor,

by mesne assignments, to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application June 10, 1931, Serial No. 543,412

' Renewed December 1, 1933 1 98 Claims.

This invention relates to grinding machines and comprises all of the features of novelty here- 'in disclosed, by way'of example; in connection with an automatic machine for grinding articles 5 suchas race rings for bearings.

An object of the invention is to provide an improved oscillating grinding machine. Another object is to provide'a grinding machine which is fully automatic and capable of reliable and efll- I cient grinding of articleshaving both curved and straight surfaces.

improved mechanism for controlling the approaching and separating movements between a work head and a tool head. Still another object is to provide an improved'work loading and ejecting mechanism for a work head. Yet another object is to provide improved mechanism for controlling the sequencejof operations in an automatic grinding machine. To these ends and also Fig. 6 is a plan view of a'portion oi'. the chuck. Fig. 7 is an endview of a portion of the chuck. Fig. 8 is a plan view of one of the clamping wedges. r v i Fig. 9 is avertical sectional view of the chucking. ejecting and locking cylinders.

10' is alsectional view 01' a check valve. v Fig. 11 .is avertical sectional view of the work head oscillating mechanism. v

|2-|z of Fig. 11. Fig. 13 is a vertical sectional viw of the cross feed mechanism.

Figs. 13A .and 13B are sectional views of workpieces. r

Fig. 136 is a sectional view of a modification on line lIC-IICcf Fig. 13D.

Fig. 13D is an end view of Fig. 130. Fig. 14 is a vertical sectional view of the grindin'g wheel head.

Another object is to provide' to improve generally upon machines of this char-' Fig. 5 is a vertical sectional view of the work head.

' a feeler gauge.

Fig. 15 is a front elevation of the ratchet feed mechanism.

.Fig. 16 is a sectional view of details associated with the feed pawls.

Fig. 1'7 is a sectional view on line ll-l1 of 5 Fig. 15. I Fig. 18 is a sectional ,view on line I8-I8 of Fig. 15,

Fig. 19 is a front view of the counting mechanism with some parts in section.

Fig. 20 is an end view of Fig. '19 with some parts removed and others in section.

Fig. 21 is a, horizontal sectional view of the cylinder of Fig. 19. i

Fig. 22 is an end view of a latch and pawl.

Fig. 23 is a side view of Fig. 22.

Fig. 24 is a side view of a control valve.

Fig. 25 is a vertical sectional view on line 25+ of Fig; 26.

Fig. 26 is a rear end view of the feed screwv retraction mechanism. 1 3

Fig. 27 is a sectional view on line 21-41-01.-

Fig. 25. I

Fig. 28 is aside-view or a pawl, lever. Fig. 29 is a vertical sectional view of the loader. 25 Fig. 30 is an end-view of the loader.

Fig. 31 is a vertical sectional view'of the main j slide-cylinder. Y i

Fig. 32 is a diagram.

This machine is more especiallvdesigned .to

operate on baltbearing cones to grind thereonan arcuate" raceway terminating in a tangent surface. Work-pieces are taken one by one from, a'magazine by a loader and presented to a chuck, the chuck gripping the work-piece as the loader 35 retreats. The work head begins to oscillate and the grinding wheel advances rapidly towards the work on a cross slide, then a feed screw 'with pawl and ratchet mechanismadvances the wheel,

' first with a coarse feed and-then with a line 40 feed until'the feed is stopped under control of The work head then continues oscillation for a predeterminednumber'of strokes while the wheel is kept advanced, thereby to produce a smooth finish. The work head is flnal- 4.5'

ly' locked in a predetermined angular position and the grinding wheel (still advanced) runs out on a main slide at right angles to the direction of =cross feed,-thereby.to grind the tangent-surface. -The wheel is quickly retractemso the feed screw reverses and the feeler gauge is lifted. The chuck releases the work and an. ejector removes it.' Suitable cylinder and piston units actuate the various mechanisms under control of valves, solenoida switches, etc. to insure 66 the proper sequence and the machine is fully.

is ground upon the work-piece W by a grinding wheel G.. The wheel spindle is journalled in a 'wheel head I4 and is driven by an electric motor I6. The wheel head is carried by a cross slide I8 which can be fed from front to rear. The cross slide is also mounted on a main slide-22 for movement parallel to the wheel axis. A

feeler gauge 24 measures the work during grinding and a magazine 26 contains a supply of work-pieces delivered one-by-one to the work head by aloader.

Work-head.-See Figs. 5, 6, '7 and 8. The hollow spindle 28 of the work-head is journalled on ball bearings 30 and 32, the outer' race ring of bearing 32 abutting against a shoulder in a housing 34 which is held from rotation by a key 36. Adjustment of the housing is effected by a nut 38 engaging the work-head. The inner race ring of bearing 32 is clamped by a nut 40 against a sleeve 42 on the spindle, the sleeve abutting against the rotor 44 of a motor 45 housed in the work-head. Another sleeve 46 engages the inner race ring of bearing 30 and holds it against a shoulder on the spindle. The outer race ring of bearing 30 is'clamped in a recess of the Work-head by a plate 50. Suitable seals retain lubricant in the bearing.

Secured to the hollow spindle 2a is a chuck 52 having a shoulder 54 to engage one'end of the work-piece W while a cylindrical surface has work-guiding inserts 51 to engage the bore. Alternating with the inserts is a series of undercut slots 58 in which wedges 60 are longitudinally adjustable, thewedges being of trapezoidal shape in cross section. The bottom of each slot 59 presents a tapered surface. to a corresponding surface on each wedge whereby longitudinal movement of the wedges (to the left in Fig. 5) will cause them to expand and grip the bore of the work-piece. A disc 62 is connected to the larger ends of the wedges and'is operated by a pull rod64 extending through the hollow spindle. The disc has a series of parallel sided slots 66 fitting necked down surfaces on the wedges,.the' resulting heads 66 on the wedges occupyi'ng.recesses 69 in the disc.

The pull rod 64 is threaded at the end into a head 10 on an" operating rod 12, a pin 14 projecting from a guide sleeve 16 into a slot of. the

head so that the rod will rotate with the spindle. The sleeve 16 is slidable in the hollow spindle and. carries a flanged collar 18 provided with a set of ejector pins which'pass through the chuck 52 to knock-01f the work. The sleeve 16 has a thickened portion 82 to guide the rod .12 and has a thin tubular extension 84 which is slotted at 86 to receive pins 88 projecting from the hollow spindle, thus to permit sliding 'ejector pins.

of the'sleeve while compelling it'to rotate with the spindle. A grooved collar 90 is fixed to the end of the sleeve and a spring 92 is interposed between the collar and an abutment face in the spindle to produce a tendency to retract the A nut 94 is threaded on the rod 12 and. a coil spring; 96 is interposed between the nut and a washer 98 abutting against the pins 88.

produce the gripping force for the chuck wedges.

the rod 12 to release the work and arms I00 The spring thus pulls on the rod to are actuated to move the collar 90 to operate theejector.

Gauge-See Fig. 5.- The work-head is split at I02 and is provided with clamping screws I04 to clamp a stud carrying a guide plate I08. The

plate has a tongue 0 furnishing a guideway for the gauge housing 24 which'is vertically adjusted by a screw II4. ,Theghousing isnormally fixed in its adjusted position by clamping nuts H6. The head of anadjusting screw II8 abuts against the guide plate I08 -to accurately locate the gauge housing so that its diamond feeler I20 will register with the desired portion of the work. The feeler is carried by a plunger I22 movable vertically through the gauge hous ing and actuating therein certain electric contacts which control functions of themachine.

The details of the gauge are immaterial to; the

present invention but will appear more fully from above the piston goes out through suitable ports past a ball check valve I36. When the flow of pressure fluid is subsequently reversed, the ball check valve closes but the fluid will enter slowly through a throttling passage I38 controlled by a screw I40. This provides for the easy engagement of the feeler with the work,

the forked arm I26 moving away from the head I24 as soon as the feeler is in contact with the work. The-mechanism inside the gauge housing is similar to that shown in patent to Hughes 1,893,205, granted January '3, 1933; it appears diagrammatically in Fig. 32 and will be later referred to.

The work head is adjustable axially on a cross slide I42 by a screw I43 and then bolted by bolts MI in the desired position depending on the nature of the work. The cross slide I42 is supported on a carrier I44 which oscillates around a vertical axis. The work-piece W, as illustrated, is a ball bearing cone having an arcuate race surface R merging with a tangent surface T. To locate work of different sizes so that the center of the arc will be in the axis of oscillation, the cross slide I42 can be adjusted on the carrier by a screw I46 and is clamped in adjusted position v by T-headed bolts I48. The carrier supports an adjustable latch plate I50 provided with a V-shaped locking notch I52 for a lock hereinafter described which holds the work head ina predetermined angular position during loading and unloading and during the traverse of the grinding wheel along the tangent surface T.

Chuck and ejector operating meana-See Figs. 9 and 24. When the work head is stopped, the chuck operating rod 12' lies opposite to the head of a screw I60 adjustably secured by a nut I52 to the enlarged end of apiston rod I84. The rod has a piston I66 in a cylinder I68 and a coil spring I10 retracts the piston, the enlarged end of the piston rod being guided in a bushing I12. At the other end of the piston rod, in a. casing I13, is adjustably secured a block of insulation I 14 carrying a contact spring I16 arranged to engage and close switch contacts at I18, the'contacts at I18 and their binding posts being carried by an insulating cover 'I 80. Advance of the piston to close the contacts and to release the work is effected by admission of pressure fluid through a port I82, another port I84 at the other side of the piston always being connected to an exhaust line.

lever below the wear plate.

The pressure fluid comes from an ejector cylinder I86.having a piston I88 which is pressed to inoperative position by a coil spring I90. The piston I88 is carried by a piston rod I92 guided in a bushing I94. The piston rod has a bifurcated head provided with a pivot pin I96 on which is pivotally suspended a lever 98. The lever is arranged to engage a wear plate 200 carried on a cross bar connecting two parallel arms I provided with studs 202 entering the groove of collar '90. The lever has a straight surface 204 engaging an abutment so that the lever cannot swing counterclockwise. As the piston I 88 advances, the lever I98 engages the wear plate 200 and swings the arms I00 to operate the ejector.

The piston I88 advances when' the chuck piston I66 advances but is initially spaced from the wear plate so that ejection occurs just after the chuck releases the work. As the lever I98 advances, a depending arm 206 thereon engages an abutment pin 208 so that the lever thereafter rocksclockwise on its pivot to bring the upper end of the The arms I 00 and collar 90 thereupon snap back under the power of the coil spring 92. Whenever the piston I88 returns, the lever I98 can wipe back under thewear plate 200, a leaf spring 2I0 yielding to allow clockwise swinging of the lever and thereafter holding the straight surface 204 against its abutment. Another leaf spring 2I2 engages a fiat face on the head of the piston rod I92 to prevent rotation thereof. Pressure fluid enters the cylin-v der I 86 through a pipe 2I4 and the other end of the cylinder is. always connected to an exhaust line through a pipe. 2I6. .The cylinders I68 and I86 are, preferably cast as a unit with both axes at a small angle to their base plate 2I5 as shown in Fig. 3 so that thepiston rods will be parallel to the work head. when the work head is locked at the same angle to the axis of the grinding wheel. This is to provide for grinding oi the tangent surface T at a slight angle. If it is desired to grind the tangent T at a diiferent angle, I

I always-in communication with acylinder 2I8 at thevspace where a valve stem 220 connects two pistons. Outside of the cylinder, the valve stem is connected to aplunger 222 adapted to be moved to the right by a solenoid 224 in a casing an exhaust line. The 'leftend of cylinder 2! is always in communication with an exhaust pipe 228 through a passage 230 and this passage also has a port communicating with the valve cylinder at a point opposite to the right hand piston. Whenthe solenoid is energized, the left hand piston blocks off the pipe 226 and the valve puts the pipe 2I4 in communication with the exhaustpipe 228. This will allow the coil springs to retract the pistons in the chuck cylinder and in the ejector cylinder. The right hand end of the cylinder 2I8 has a port 232 leading to another cylinder and when the solenoid. acts, this port is open to an exhaust line as will appear. when the valve is to be restored to its left hand position, the port 232 is in communication with a pressure line and the piston valve is forced back.

Lock mechanism for positioning and locking work heart-See Fig. 9. A lockoperating'cylinder 238 contains a piston 24.0 on a piston rod 242 which has an enlarged portion forming alocking "plunger 244 having a bevelled end 246 arranged to advance into the notch I52 of the latch plate I50. The work head stops oscillation in approximately the exact position desired but the bevelled end 246 will act as a cam to insure its correct location and lock it in position. The piston rod 242 is keyed from rotation and extends into a casing 241 where it adjustably carries a block of insulation 248 supporting a contact spring 250.

The contact spring is arranged to engage and to pipe 256. When pipe 256 admits pressure fluid,

the ball check valve closes and the fluid is slowly admitted through a throttling passage 266 controlled by an adjusting screw. The resulting slow forward movement of the locking plunger provides time for the bevelled end 248 to turn the work head, if need be, to the exact position desired. As above stated, the locking cylinder 238 is connected to one end of the control valve cylinder M8 by the port 232- so that whenever the locking piston is. retracted, the control valve is retracted. The four cylinders last described are all carried by a casting which is bolted to a pan 261 which is rigidly secured with respect to the I frame I0. V

Oscillation of work head.-See Figs. 11 and 12. The carrier I44 which supports the work head is secured by bolts 210 to a flange 21I on the upper end of a hollow rockv shaft .212, The shaft is journalled for oscillation on a ball bearing'214 whose outer race ring is supported in a recess of a hollow casting 218 which is bolted to the frame I 0. Another ball bearing 218 has its inner race ring locked against a shoulder on the shaft by a nut 280. The outer race ring engages a shoulder in a bearing housing 282 which is slidably adjustable in the hollow'casting 216 and held from rotation by a key 284. A

nut 286 is threaded on the housing 282 and en-.

gages the casting 216' to put an initial load on the bearings. The nut is 'held by a locking plate 288. A flanged washer 290 carrying a packing is held up against a shoulder'in the casting 216by coil springs 292. The rock shaft 212 is rockably supported at its lower end in a pair of ball bearings 298 whose inner race rings are held on the shaft by a nut 300, a washer 302 being interposed between one of the rings and a shoulder on'the shaft. When assembled, these hearings are under an initial load and the outer race rings have a sliding flt in a sleeve 304 having a supporting flange 305. A coil spring 306 presses a washer 308 against the washer 302 to seal the bearings. The flange ofisleeve 304 has a fluid collecting groove 3I0 leading to a drain pipe. A closure plate 3I2 covers the lower ends of the bearings and has a hole leading to the hole which extends through the rockshaft so that electric wires may be passed up-conveniently to. the work head.

A cylinder 3 is secured by screw bolts 8| I There are two partition blocks 328 fixed in the cylinder head 328', the latter having arcuate slots traversed by clamping bolts 322 to clamp the cylinder in angularly adjusted position on a plate 323 supporting the flange 385. A sleeve 324 is keyed to the rock shaft inside the cylinder and carries two vanes 326 for rocking .the shaft.

cylinder and provided with upper ports 338 and lower ports 332 which conduct fluid pressure alternately to the sides of the vanes under control of .a valve. The lower cylinder head has branch passages 334 leading to the lower ports and the upper cylinder head'has branch passages 336 leading to the upper ports. When fluid pressure is alternately admitted at the ports 338 and 332, the vanes and the shaft are oscillated.

Fixed to the middle of the rock shaft is a split hub 342 carrying a cam 344 engaging a roller on an operating ann 346. This is the arm which actuates feed pawls as will later appear. The hub 342 also carries an arcuate arm 348 provided with three adjustable dogs of which one end dog 358 and a central dog 352 are shown in Fig. 11. The dogs 358, as will appear, control switches which in turn control a main reversing valve. The central dog 352 engages a roller 354 on a switch enclosed in the casing 356, this switch becoming effective only during a spark-out or polishing action as will appear.

Wheel head.-See Figs. 13 and 14. The grinding wheel G is guarded by a hood 318 attached to the wheel head I. The wheel is secured to a spindle 312 journalled on ball bearings 314 and 316 carried in a quill 318 which is keyed from rotation by a pin 388 and locked by a screw 382. The outer race ring of bearing 314 is clamped by a nut 383 against a shoulder in the quill and the inner race ring is locked against a shoulder on the shaft by a nut .384. The inner race ring of hearing 316 is clamped to the shaft by a pulley 386 which is secured on the shaft by a nut a shoulder in a bearing housing 398 which is' axially adjustable in the quill. A part ofthe bearing housing is threaded into a nut 392 which rests against a shoulder in the quill. Before sliding the quill into the head l4, the bearing 'housing 398 can be turned with the aid of the spanner holes 394 to put an initial load on the bearings. The holes are accessible through a slot 396 in the quill, and the bearing housing is locked by a screw 398. The bearing is sealed by a felt washer in a nut 488. o v 1 Wheel head retraction and cross feed.-See Figs. 13, 14, 15 and 18; The cross slide l8 supporting the wheel head has a dovetail slot 418 with a gib 412 at one side of a dovetail guide 4 I 4 extending crosswise of the main slide 22. The head carries a jump-back cylinder 6 containing apiston 4l8 with a piston rod 428 extending rearwardly through a gland.4 22 and attached feed screw. The slide plate occupies a' slot in the bottom of the crossslide l8. The feed screw is journalled for rotation without endwise movement by a double row bearing 436 supported in an upright bracket 438 of the main slide 22, the

outer race ring being securedby a plate 448. The inner race ring abuts against a collar 442 on the shaft and is held by afgear 444 and by a flanged bushing 446 which is-locked by a nut 448. A sleeve 458 is iournalled for rotation around the bushing and carries a pinion 462 at one end to mesh with a gear 454 (Figs. 15 and 18) 'journalled on a stud 455 and carrying a pinion 456 which meshes with the gear 444, thereby providing reduction gearing for the feed screw. A ratchet wheel 458 is secured to a hub member \,468 which is keyed to the sleeve 458. A hand wheel 462 is also fastened to the hub member. Ratchet feed mechanism-See Figs. 15, 16 and 17. The ratchet wheel 458 is advanced by a pair of pawls 418 and 412 which receive alternate feed impulses from the oscillating head and the rock arm 346. The arm is secured to a rock shaft- 414 journalled in a boss of a bracket 416 on the frame l8 and carrying an arm 4.16 having a pin and slot connection488 with a lever 482. A lug 484 on the bracket 416 is bored to provide guides for plungers 486 and 488. The plunger 486'abuts at one end against the arm 418 and abuts at the other end against the lower end of a lever 498. The plunger 488 abuts at one end against the lower arm of lever 462 and abuts at its other end against the lower end of a lever 492. The levers 498 and 492 are pivoted on a stud 494 and their upper ends pivotally support the pawls 418 and .412. A spiral spring 496 is attached to each lever and to one of the pawls to hold the pawls against the ratchet wheel. A coil spring 498 is attached to each lever 498 and 492 and to the bracket 416 to draw the pawls to a retracted position ready to feed. One pawl is retracted as the other advances and hence a feed stroke occurs when the arm 346 swings in either direction. In the retracted position, each lever 498 and 492 rests against an adjustable stop screw 588. The stroke of the pawls can be reduced automatically by interpos ing a stfip in the path of the returning levers 498 and 492. This stop comprises a blade 582 adjustably secured by screws 584vto a lever 586 pivoted on the bracket 416. The lever has one arm provided with an armature 588 adjacent to a magnet 5l8 so that, when the magnet is energized, the lever will swing the stop blade 582 upwardly to restrict the stroke of the pawls and so reduce the feed. The mag- 'net is desirably controlled by the gauge to reduce the feed a little before the piece reaches final size. To stop the feed entirely when the gaugeindicates that the piece is down to size, a second magnet H2 is energized to swing a bent lever 5l4. One arm of the lever supports screws 5l6 whose ends 5l8 are bent to hook around oilset plates 528 carried 'on the feed pawls. Thus the pawls are moved automatically away from the ratchet wheel. The pawls can also be retracted manually by an arm 522 on a shaft carrying an eccentric cam 524 to swing the bent lever 5. The rock shaft is conveniently journallcd'in a cover plate 526 which encloses the feed mechanism. I

Spark-out counting mechanism-See Figs. 19, 20, 21, 22 and 23. A counting mechanism is provided in order to make the wheel head oscillate a predetermined number of strokes after the feed is stopped and before the wheel is backed away. This is to produce a spark-out or polishing action and contributes to a smooth finish on the work. .When the feed stops, the continued oscillation of the workhead repeatedly energizes a solenoid 359B andawings an arm 532 which is end of the machine.

turns and a detent 558 prevents the ratchet wheel from returning. Adjustably secured to the ratchet wheel'by a screw 552 is a sector plate 554 carrying a lateral cam or shield 556 arranged to engage an arm 558 on a latch 568 thereby releasing the head 562 of a valve stem 564. The latch is pivoted at 566 and is notched to receive the detent- 558 which is pressed towards it by a leaf spring 566. The end of the detent has a. wide head 518 with inclined abutment faces 512 resting against similar faces on the latch arm. As a consequence, the latch arm 588 releases the detent 558 when the latch is released and the spiral spring can return the ratchet wheel against a stop as soon as the pawl 538 is raised. The pawl is released by a depending lug 514 on the head of the valve stem which is forced out'by a coil spring 516 in a valve cylinder 518. The head of the valve abuts against the plunger 588 of a solenoid 582 which is ener-' head as will appear. The valve cylinder 518 has two connected ports 598 for exhaust of fluid and also has a central inlet port 592 for admitting pressure fluid. In the position illustrated, pressure fluid is directed between the two right hand pistons to a passage 594 leading to a series of cylinders and exhaust fluid comes back through a passage 596 to the space between the two left hand pistons. When the valve is slid to the left, the course-of fluid is reversed in the system as will later appear more in detail.

Reversal of feed screw and resetting of feed ratche't.See Figs. 25, 26, 27 and 28. Although the jump-back cylinder 4l6 of course retracts the wheel'from the work, it is also desirable to rescrew extends rearwardly through a sleeve 688- which is integral with an oscillating vane 682 in a sector shaped cylinder 684 having the fluidsupply pipes 606 and 688. The cylinder has heads M8 and H2 provided with packing glands 6H for the'sleeve 688, and one of the heads GM has lugs 6|5 fastened to the rear side of the main slide 22. The extended end of the sleeve is keyed to a collar 6l6 having a fork 6|8 receiving a lever 628 pivoted at 622' to the arms of the fork. A

leaf spring 624 tends to press a tooth 626 at one end of the lever into engagement with the teeth of a ratchet wheel 628 fixed on the rear end of the feed screw by a nut. The other end of the lever has its sides bevelled as indicated at 638 and is initially held up by a rounded screw 632 on a bracket 634. The vane and its sleeve are turned at the end of the grinding operation by fluid I pressure, the collar 616 and the lever 628 turning The lever is disengaged at any desired point in the oscillating movement by a rib 636 carried on an arcuate plate 638 which is slotted at 648 andv fastened in adjusted positionto' the'cylinder head 6l2 by screws 642. The bevelled sides 638 of the lever act as cams when they engage either the rib 636 or the screw 632. As shown in Fig.- 26, the arcuate plate is adjusted so that the feed I screw will be reversed through a small angle but a straight tapering surface S, a minor jump back of the wheel head is employed. This retracts the wheel a slight distance from the deepest. part of the arcuate surfaceR just prior to the runout of the main slide 22. This action can be employed by threading the rear end of the piston rod 428 in a nut 643 which is rotatably mounted in the lug 428 of the slide plate 438. 'The nut is connected to a vane 644 in a small sector-shaped cylinder 645 while the rod 428 is splined to the cylinder head 646. Pressure'fiuid is admitted to one side of the vane just prior to the run-out'of the wheel with the main slide so that the surface S, instead of being tangent to the arcuate surface R is parallel to such a tangent. A snap-rib or hook H is thus obtained which will hold the balls of the bearing in their raceway when the other parts of the bearing are assembled as is well understood in the bearing art. The amount of this minor retraction of the wheel will usually be very small and can be regulated or eliminated by adjustable stop screws 641 which limit or prevent the movement of the 'vane. Aswill appear .in the diagram, the action of the vane can be controlled by a suitable spring-closed check valve 648' so that pressure fluid will go to the vane before opening the valve and continuing on to operate the main slide. When the main slide re-. turns, the vane is reversed.

Main slide.See Figs. 2, 4 and 31. The main slide 22 slides on ways on the main frame and is actuated by a piston 658 in a cylinder 652. When pressure fluid is admitted through a pipe 654 and passages 656 to one end of, the cylinder,

exhaust fluid from the other end of the cylinder goesthrough a passage 658 to a pipe 668. A piston rod 662 is adjustably connected to a bracket 664 on the main slide 22 and movement of the slide in one direction is limited by a stop screw 666. The main slide has a casing 668 of insulating material adjustably supporting a series of insulating blocks or dogs 618. One' dog opens and closes switch contacts at 612, another. closes and opens switch contacts at 614; a third opens and closes switch contacts at 616 and a' fourth opens and closes switch contacts at 618. The purpose of these will appear later.

Loading mechanism.See Figs. 29 and 30. A loader for presenting work-pieces to the chuck is carried by the main slide and a part of the loader projects over and clears the cross slide I8. A cylinder 188 has piston 182 with a piston rod 184 to the end of which a bent arm 186 is secured by a screw 188. A work carrier 1"; is rewhich are alternately energized under control of -the coil spring 124 movably secured tothe arm 186 and is open at the end and at the top, as at "2, tofreceive a:

work-piece W from the magazine 26.. The magazine is secured in vertically adjusted position on a bracket 1|3 by bolts 1 and the bracket is adjustable lengthwise of the cylinder by boltsv 116. Leaf springs 1l8 inslots of the carrier hold the work-piece at its bottorrr'and sides. The carrier has a top wall or guard 128 with a cam at one end to raise and hold back .the remaining Fluid pressure enters the cylinderat 138'to'a dvanceth-e loader while exhaust fluid goes out at 132. The loadercarrie's the work-piece to the chuck and; assoonas the chuck stops the piece, yields but holds the piece while the chuck. grips it. The ends of the leaf springs 1 I 8 are rounded so that they are cammed outwardly by contact with the chuck and will ride back outside the held piece when the loader is retracted. The piston rod 184 is extended into a casing 196 and carries a-block'of insulation 138 supporting a contact spring. 148. The spring is arranged to engage a pair of switch contacts at 582A on an insulating cover 144'or to engage a pair of switch contacts at 224A on an insulating cover 148. The switch contacts control the before mentioned solenoids 582 and 224. respectively, as will appear. The loader basehas longitudinal slots 158 'for T-headed bolts 152 whose heads 156 are adjustable laterally in cross slots 158 in a supporting plate '168. The supporting plate 168 is secured to the main slide 22 by bolts 162 in cross slots. The bolt and slot connections permit the loader to be adjusted at the same angle as the chuck.

Fluid pressure and. wiring diagram-See Fig. 32. Pressure fluid from a pump passes through a piston shut-off. valve 822 which is normally held open by a solenoid 824 under control of a switch 826. The pressure fluid is conducted by branch piping to a. series of control valves, and exhaust branches of the piping return the spent fluid.-

The letter P indicates those branches in which fluid is always under pressure and the letter E indicates those branches in which the fluid is always free to return to the exhaust line. In other pipes, the fluidis alternately under pressure and free to exhaust.

A main reversing valve 832 controls the-oscila lation of the work head. The details of this valve need not be gone into but it will suflice to say it comprises asliding piston valve 834, an operating piston 886 therefor, and a hollow control valve 888 having an operating rod 848. The rod 848 reciproc'ates under control of solenoids A and B switches C and D actuated by the dogs 358 on the oscillated shaft 212. Pressure fluid from thereversing valve832 alternately passes through pipes 842 and 844 and through an interposed shut-oi! valve 846 to passages in the upper and lower heads of the cylinder 8 containing the two vanes 326. The dogs 858 close the switches C and D alternately and thereby energize the solenoids A and Bto reverse the flow of fluid and change the direction of swing of the work-head.

75 The solenoids are connected to branches of a together at 862.

the work head so as to line up with power line -having a switch 858. During the;

oscillationof the, head. the'third dog 352' repeatedly throws the switch 356 but the switchis' not effectiveto operate itssolenoid 356B-until another switch'356A is closed as will'appear.

' During grinding and with the wheel-receiving a coarse feed by the pawls, the feelergauge' follows the diminishingwork} its contact icontrolf arm 868 swinging to the'l'eft'andynear the 'end' of the grinding operation, brings the contacts A circuit 'is'thus completed from low voltage line wires 864 and 866 through a relay magnet 868 to close a relay switch 818. Magnet 5| 8 is thereupon energized to swing the lever 586 and reduce the cross feed by restricting the I movement of both feed .pawls. When the work .is down to final size, the contact control arm 868 separates a'pair of contactsat 816 and thereby breaks a circuit which was holding energized a relay magnet 818. Therelay switch thereupon...

brings together contacts at 888 to energize the magnet 512 which thereupon stops the feed by retracting the feed pawls. The separation of the gauge contacts at cuit from the line wires to a relay magnet 884,

' thereby bringing two contacts together at 356A 816 also breaks a branch cirand rendering the contacts at 356 alive ready to repeatedly energize the solenoid 356B as the work-head continues to oscillate after cross-feed ceases. The number of spark-out strokes is controlled by the timing ratchet wheel 548 whichl trips the latch 568 to release' the main control valve stem 564 and so reverse the flow of fluidin the piping. The'stemsli'des-to the left under pressure of its. spring 516 and opens the switch contacts at 588. This de-energizes a solenoid- 586A and allows a coil spring 892 to close the shut off piston valve 846 and stop oscillation of the work head.

Other things occur when the valve stem 564 is advanced by its spring. Pressure fluid is directed between the two right hand pistons through a pipe 894 and its branch pipe 256 to the left end of the locking piston 248, exhaust fluid leaving the right side of such piston through the branch 258 of a pipe 898 and going around the coil spring 516 to the permanent exhaust line E. The' 248 advances the 'lock slowly (by.

locking piston reason of the throttled passage 266) to accurately locate and lock the work head in positionfor further operations on the work. As the lock advances, it closes the switch contacts at 252 and "a circuit is-completed through branches of the main power line to energize a'solenoid 252A and slide a valve stem 988 to the left in a cylinder 98L The fluid can exhaust from the left of the valve cylinder through a passage 982 and through a. branch 898A of pipe 898 which is then an exhaust line. Pressure fluid enters the valve cylinder 98l through the pipe 894, first going around another valve stem 984 and througha passage 986 to'the space between the two middle pistons on the stem 988. The fluid 'is then directed into the pipe654; first operating the vanes in sector cylinder 645, optionally, for minorwheel retraction, then opening check valve 648 and going to the main slide operating cylinder 652. The

ring is ground." Exhaust fluid from the main slide cyl nder 652 passes out into the pipe 668 which is a branch of pipe 898.

As the main slide starts out. it separates switch contacts at 612 and releases a vertical valve stem' piston 658 in this cylinder is moved-to the-right a during which time the straight part'of the race' 9 by de-energizing a connected solenoid 812A which previously was held energized by branches of the main power line. The valve stem 9 descends by gravity blocking its cylinder 9I8 .off

from a branch 8983 of pipe 898 and putting a pipe 9I8 in communication with the permanentv When solenoid 81413 is energized, it moves a valve stem 9I8 to the left in its cylinder 9I9 and places the permanent pressure line P in communication with a pipe 928 leading to the rear of the jump back cylinder 8 and so retracting the wheel head. Exhaust fluid from the jump back cylinder returns through pipe 924 to the right of both valve pistons and so enters the permanent exhaust line E.

Solenoid 814A also being energized, the valve stem 984 which has four pistons is moved to the left. Pressure fluid from pipe 894 is now directed between the two middle pistons and through a pipe 928 to the feed screw retractor vane 882 and to the gauge moving cylinder, thus reversing the feed screw and lifting the gauge stem bodily. Pressure fluid in pipe 928 opens a check valve 928 against the pressure of a coil spring 988 and continues through the pipe 228 to the control valve cylinder 2I8 of the chuck and ejector. The fluid passes between the two-pistons ofthe control valve and through the pipe 2 to advance the ejector piston I88; the fluid also continues on through the passage I82 to'advance the chuck piston I88. The flnished workpiece is thus released and ejected. The space at the right of the two pistons I88 and I88 is in communication through the pipes 2 I8 and 228 with thepermanent exhaust line E and the coil springs are compressed.

While the chuck piston I 88 is advancing, its stem closesswitch contacts at "8 and energizes a solenoid I18A which is thus placed in circuit with branches of the main power line. The solenoid I'I8A pulls out on a valve stem 944 of a cylinder 948 and puts a branch of the pressure line P into communication with two other cylinders. A pipe 948 conducts the pressure fluid to the loading cylinder I88 at the right of its piston to advance the loader with a new work-piece. Exhaust fluid goes back through a pipe 958 and past the end piston on the stern 944 to the permanent. exhaust line E. At the beginning of its advance stroke, the loader piston rod I84 separates switch contacts at 582A these being already dead however because of the separation of con- I tacts at 582B controlled by a contact operating piston 952. This last piston advances when the loader advances but a throttle valve 954 retards it so that an insulating plate 958 on its piston rod does not make the contact at 5823 until the loader has separated the contacts at 582A. Hence switch contacts at 582A do not become effective until the loader is subsequently retracted to again close the contacts at 582A. At the end of its advance stroke to the left, the loader closes the switch contacts at 224A- and energizes the solenoid 224 thereby moving the chuck. valve piston inwardly to the right. This blocks ofi fluid pressure at the pipe 228 from access to the' chuck cylinder and ejector cylinder but places passage I82 and pipe 2I4 in communication with whereby the chuck grips the new work piece'and 7 the ejector is reset. (The solenoid can thus move the valve to the right without opposition from fluid pressure because the passage 282, connects the right hand end of the cylinder 2I8 with the corresponding end of the locking cylinder then ex- 1 hausting to pipe 288.)

As the'chuck piston I88 thus returns to'the' left by springpressure, the contacts at I18 are opened and solenoid I'I8A,is de-energized. A coil spring 958 thereupon shifts the valve stem 944 inwardly. Pressure fluid then passesfrom the pressure line P through pipe 958 to return the loader to the right to its retracted position.

Exhaust from the loader cylinder is through pipe 948, past the piston 982, and through coil spring 958 to" the permanent exhaust line E. As the loader retreats, it opens switch contacts at 224A, de-energizing solenoid 224 and then closes switch contacts at 882A to energize solenoid 582. (The contacts at 88213 are .still held closed by piston 982 because both sides of the piston are then open to an exhaust line and in practice the stem of piston 982 is horizontal so that gravity does not tend to retract it). Solenoid 882 restores .the stem 884 of the main control valve to latched position and thus immediately puts the pressure line P in communication with the pipe 898 and its branches, while pipe 894 and its branches have access to exhaust line E. Pressure fluid entering pipe 288 quickly retracts the locking .piston 248 (opening switch'contacts at 282) and pressure fluid in passage 232 retracts the chuck control valve, theport 288 at the left end of the cylinder being always open to pipe 228 and exhaust line E. Pressure fluid in branch pipe 898A slide cylinder 888 to advance the main slide. Pressure fluid also goes through a branch pipe 88I to the cylinder 848 to restore the vane 844 and nut 848. Exhaust from cylinder 845 is through pipe 854 and a branch 884A to the space between the two right hand pistons on the stem 988 and then to the permanent exhaust line E. Exhaust from the main cylinder 882 is through the closed check valve 848 to a permanent exhaust line E. When solenoid 882 is energized to restore the main control valve stem 884,- switch contacts at 888 are closed thereby energizing solenoid 588A to open the shut ofl. valve 848 and start oscillation.

As the main slide advances, switch 814 is opened and solenoids 814A and 8143 are .de-

energized. (Pressure fluid in pipe 898A can operatestem 984 even if solenoid 814A isvenerglzed.) A coil spring 958 then restores valve stem 9| 8 to the right. Pressure fluid in the pressure line P is then directed through the pipe 924 'to the jump back cylinder 8 to advance the wheel head. Exhaust fluid in pipe 928 goes through the coil spring 958 to the permanent exhaust line- E. Meanwhile the feed screw retractor and gauge are held inoperative because the pistons 01' valve stem 9I4 of solenoid 812A are still depressed to obstruct the adjacent branch 8983 of pipe 898 from access to pipe 9I8. Asv the main slide completes its advance to the left, it closes switch contacts at 812 and energizes sole-.-

noid 812A to raise the valve stem 9. Thereupon the pressure fluid in pipe 8983 is placed in communication with pipe 9I8 and its branch 9 I 8A. The piston 952 is thus actuated to separate f the switch contacts at 5823. The pressure fluid in the pipe 888' which is a branch of pipe 9I8 also resets the feed screwretractor vane to I slide retreats,

for turning the d. the feed screw and starts when the main slide advances. contacts at 818 and 818 are closed by thedogs the heads with on the threaded the gauge stem to the work, the movement of the reason of the throttling gauge stem being slow by action in the passage ISL Exhaust from the gauge cylinder and from th'vane occurs through the branches of pipe 828. Check valve!" closes by pressure of its coil spring I 930 as soon as pipe 928 and its branch 828A are connectedto the exhaustline E by the restoration of valve stem Bill. The motor inthe work head is shut ofl'when the main slide. 22 retreats and onthe main slide 22 when the main slide advances and a circuit is completed through a relay 912 to close a relay switch 014. Currentfrom theline wires 918 then starts themotor. when the the switch contacts at 818 and 81! are separated and the relay switch 914 is opened to stop the motor. A push button switch 91! can also .be used to control the. relay to start or stop the motor.

I claim:

1 In a machine of the character described, a work head, a tool head, feed mechanism, means for operating the feed mechanism in one'direction to produce a relative feeding movement of approach between the heads, mechanism independent of the.feed mechanism and comprising a cylinder and piston unit directly connected to one of the heads for separating the heads in the line of feed, and mechanism for operating the feed mechanism in the opposite direction; substantially as described.

2. In "a machine of the character described, a work head, a tool head, a feed screw, mechanism feed screw in one direction to effect a relative feeding movement of approach between the heads,

directly connectedto one of the heads for separating the heads in the line of feed, and mechanism for turning the feed screw in the opposite direction; substantially as described;

3. In a machine of-the character described, a work head, a tool head, a feed screw, pawl and ratchet mechanism for turning the feed screw in one direction to eifect a relative feeding movement of approach between the heads, mechanism independent of the feed screw for shifting one of respectto the screw and so separating the heads in the line of feed, and fluid pressure mechanism for turning the feed screw in the opposite direction; substantially as described. I n

4.. In a machine work head, a tool head, mechanism .for 'eflecting a feeding movement of approach between the heads, mechanism for effecting a minor move- A ment of separation between the .heads, and mechanism for effecting .a major movement of separation between the heads, said last two mechanisms comprising a piston having a piston rod with a threaded portion,and a rockable nut portion; substantially ,as described. J

5. In a machine of'the character described, a work head, a tool head, a feed screw, mechanism for turning the feed screw tojeifect a relative feeding movement of approach between the heads, mechanism for effecting a minor separation of the heads in the line of feed, mechanism for causing a relative shifting movement of the heads in another direction for a machining oper- The switch 'head, a plate having mechanism independent of of the character described, a 1

. hasten the feed and fluid in a branch QIUC lowers eifecting a major separation=of the heads in the I line of feed; substantially as described.

for turning the feed screw to effect a relative 6. In a machine of the character'described,l a workhead, a tool head, 'a feed screw, mechanism feeding movement of approach between the heads, mechanism for eflecting a minorsepara'a tion of the heads in the line of feed, mechanism unit for effecting amajor movement of separa- I ,9 for effectinga major separation of the heads, and

mechanism for reversing the feed screw; sub-.1

tion between the heads, and; means for causing a relative shifting of the heads to occur in a longitudinal direction betweenthe operation ofthe two separating mechanisms; substantially as described.-

- 8. In a machine ofthe characterdescribed, a workhead, a tool head, means for causing relative movement of the heads and comprising a piston, a. piston rod and. a cylinder, a portion of the piston rod being threaded, a nut threaded 'on the piston rod, and means for turning the nut for causing a subsidiary relative movement of the heads; substantially as described.

'9. In a machine of the character described, a sliding engagement with the head, means for causing relative movement between the head and the plate and comprising a piston, a piston rod, and a cylinder, the piston rod being threaded, a nut threaded on the piston rod and'supported by the plate, and means for causing relative rotation between the nut and the rod for effecting asubsidiary relative movement of the head and the plate; substantially as described. 10. In a machine of the character described, a work head, a tool head, a feed screw, mechanism at one end of the feed screw for turning the feed screw in one direction to effect a relative feeding movement of approach between the heads,

mechanism at the other end of the feed screwv for turning the screw in the opposite direction, the intermediate portion ofthe feed screw having threaded connection with one of the heads; sub- 0 stantially as described.

11. In a machine of the character described, a work head, a tool head, a feed nut, a feed screw, means forturning the screw in one direction to effect a relative movement between the heads, a cylinder,' and a vane in the cylinder and having a one way connection with the feed screw for turning the screw in the opposite direction; substantially as described.

12. In a machine of the character described, a work head, a tool head, a feed screw, a cylinder, a vane rockable on the feed screw, and means for clutching the vane to the feed screw; sub--- stantially as described.

13. In .a machine of the character described, a work head, a tool head, a feed screw, a cylinder, a vane rockable on the feed screw, and means for clutching the vane to the feed screw and comprising a ratchet wheel carried by one of said last members, and a movable dog connected to the other; substantially asJzlescribed,

14.-In a machine of the character described, a work head, a tool head, a feed screw; a cylinder, a vane, and means for clutching the vane to the feed screw and comprising a ratchet wheel car- 

